document.write( "Question 215098: Find the equation of the line with contains
\n" ); document.write( "P(-1,3)and Q(1,1)
\n" ); document.write( "

Algebra.Com's Answer #162526 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
\r
\n" ); document.write( "\n" ); document.write( "First let's find the slope of the line through the points and \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Note: is the first point . So this means that \"x%5B1%5D=-1\" and \"y%5B1%5D=3\".\r
\n" ); document.write( "\n" ); document.write( "Also, is the second point . So this means that \"x%5B2%5D=1\" and \"y%5B2%5D=1\".\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29\" Start with the slope formula.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"m=%281-3%29%2F%281--1%29\" Plug in \"y%5B2%5D=1\", \"y%5B1%5D=3\", \"x%5B2%5D=1\", and \"x%5B1%5D=-1\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"m=%28-2%29%2F%281--1%29\" Subtract \"3\" from \"1\" to get \"-2\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"m=%28-2%29%2F%282%29\" Subtract \"-1\" from \"1\" to get \"2\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"m=-1\" Reduce\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So the slope of the line that goes through the points and is \"m=-1\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now let's use the point slope formula:\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y-y%5B1%5D=m%28x-x%5B1%5D%29\" Start with the point slope formula\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y-3=-1%28x--1%29\" Plug in \"m=-1\", \"x%5B1%5D=-1\", and \"y%5B1%5D=3\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y-3=-1%28x%2B1%29\" Rewrite \"x--1\" as \"x%2B1\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y-3=-1x%2B-1%281%29\" Distribute\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y-3=-1x-1\" Multiply\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=-1x-1%2B3\" Add 3 to both sides. \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=-1x%2B2\" Combine like terms. \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=-x%2B2\" Simplify\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So the equation that goes through the points and is \"y=-x%2B2\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " Notice how the graph of \"y=-x%2B2\" goes through the points and . So this visually verifies our answer.\r
\n" ); document.write( "\n" ); document.write( " Graph of \"y=-x%2B2\" through the points and \r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );